With drought becoming more common, cities will need to invest in multiple endeavors to ensure their water supplies can meet the growing needs of what are projected to be significantly larger populations. That will mean more major water recycling efforts, technologies that conserve water and systems to harvest water. It will so require responding to the root causes of climate change and building new infrastructure to protect water supplies and keep them safe from contamination. With demands for water certain to increase for residential, industrial and ecological uses, hydrologist Enrique Vivoni, a Fulton Schools professor, says cities must devise master plans designed to provide and secure water resources for as many as 50 to 100 years into the future.